Electromagnetic-wave generating system for the transmission of speech



Sm. 19% 3mm I I M. LATOUR ELECTROMAGNETIC WAVE GENERATING SYSTEM FOR THE TRANSMISSION OF SPEECH Filed July 15, 1920 Patented Sept. 28, 1926.

UNITED STATES PATENT OFFICE.

MARIUS LATOUR, OI PARIS, FRANCE, ASSIGNOB 'IO LATOUR CORPORATION, 01 JERSEYCITY, NEW JERSEY, A CORPORATION 01' DELAWARE.

ELECTROMAGNETIC-WAVE GENERATING SYSTEM FOR THE TRANSMISSION OF Application filed. July 15, 1920, Serial No. 896,489, and in France February 15, 1916.

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The present invention relates to an improved system of generation for speech transmission by means of electromagnetic waves utilizing thermionic tubes or elements, and relates particularly to a particular method of feeding the anode filament circuit of the generator.

According to the present invention the generator is formed by three lamps or groups of thermionic tubes the anodes of which are coupled in parallel, their circuits, comprising a common part suitably coupled to the transmission aerial and the anodes of each of these tubes or groups of tubes, are fed respectively by each of the phases of a three phase generator of suitable voltage. The current generated is moreover control ed according to speech rhythm'by means of a suitable modulating arrangement.

The new characteristics of-my invention are shown in particular in the following claims. Moreover the invention itself, with other details as to its aim and is advantages, will be better understood by referring to the following description drawn up in accordance with the drawing in which I have illustrated in diagrammatic form the preferred construction of my invention.

As is shown in the drawing, the three tubes composing the generator each comprise an anode 2, a grid 3 and filament 4 raised to incandescence by means of a source of continuous current 5 which serves for the feeding of all the filaments of the generator.

The grids 3 are all connected to the filaments 4 through the intermediary of acommon' inductance 16. In the same way the anodes are interconnected to a common inductance 8 which is connected on the other hand to the filaments. This inductance 8 is suitably coupled reactively or regeneratively on the one hand to the inductance of the grid 16 and on the other hand to an oscillating circuit.

In the example shown the oscillating circuit is formed by the aerial 6 and earth 7 of a wireless telegraphy station and the common inductance 8 serves to couple this. with the generator.

According to thepresent invention in the connection joiningeach of the'anodes (or each of the groups ofanodes) 2, 2, 2, to the common inductance 8'is interposed one phase winding of a three phase alternating current generator 17 connected in star, and the neutral point of whlch is connected to the filament circuits by means of the winding 8.

tubes) functions in turn at the moment-- 7 when the voltage reaches its maximum in the corresponding fraction of the winding ,17. There is thus in the working circuit 6, 7, 8 a continuous emission of oscillations the frequency of which is the natural frequency of the circuit 6, 7, 8. This emission lends itself admirably to the transmission of speech by Hertzian waves. It is suificient to modify in any suitable way the amplitude of the oscillations produced according to speech waves.

In 10, 11, 12 is shown by way of example a method of carrying out such a modulation arrangement. According to this particular form between the grids 3 and the filaments 4 of the generator an impedance is connected formed of an inductance 10 and a capacity 11 tuned to the wave length of the generator. A microphone 12 is connected in series either with the inductance 10 or the capacity 11.

This impedance can easily be made very large and of the order of magnitude of the resistance of the lamp between the grid and the filament. Under these conditions the value of the impedance is proportional to the resistance of the microphone and the variations of the resistance of the microphone are translated by the corresponding variations of the impedance. It can therefore be said that the result is as if for amicro hone of ordinary resistance a microphone 0 very great resistance has been substituted (the order of magnitude of resistance of the lamp between the grid and the filament) and which is very appropriate for shunting the grid filament circuit and generator.

As has already been stated above the particular method of modulation is given only by way ofexample and allmethod's f nio'du- {the present invention.

comprising. the combination of a group of Having now particularly describedand ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. A generator of continuousoscillations thermionic tubes including anodes, grids and filaments of which the filaments are connected electrically together, a source of polyphase alternating current, the anodes of each tube being connected respectively to one of the phase windings of said source of polyphase alternating current, a common inductance connecting all the phase windings electrically to the filaments of the tubes, and a second inductance electrically included in a connection between said grids and said filaments.

2. A generator of continuous oscillations comprisin in combination a number of thermionic to es including anodes, grids and filaments, having the filaments electrically connected, a source of polyphase alternating current having one phase winding connected to the anode of each tube respectively, a common inductance connecting all the phase windings electrically to the .filaments of the tubes, a second inductance coupled to said. first inductance and connected electrically to said grids and said filaments.

3. In a signaling system, a generator of high frequency continuous oscillations applicable to wireless telephony comprising in combination three thermionic tubes each including anodes, grids and filaments, of which the filaments are connected electrically to gether, a source of three phase alternating current having its windings connected to the anodes of the several tubes respectively,

a common inductance connecting the three phase windings electrically to the filaments of the tubes. and a second inductance serially included in a connection between said grids and filaments, and means to control the oscillations according to speech waves.

4. In a signaling system. a generator oi high frequency continuousoscillations applicable to wireless telephony comprising in combination three thermionic tubes each including anodes. grids and filaments of which the filaments are connected electrically tov gether, a source of three phase alternating current having each of its phases connected to a different one of said anodes respectively,

a common inductance connecting the three windings of the phases electrically to the filaments of the tubes, and a second induc- -tance coupled to said 'firstinductance and serially includedfin a connectiombetween said grids and said filaments to produce oscillations, means to control the oscillations according to speech waves, and a radiating system for said controlled oscillations electrically. associated with said first inductance.

which the filaments are connected electrically together, a source of polyphase alternating current having one of its phase windings connected to the anode of each tube respectively, a common inductance connecting all the windings of the phases'electrically to the filaments of the tubes, and a second inductance electrically connected on the one hand to the grids and on the other hand to the filaments of all the tubes, an oscillating circuit connected to' the common part of the anode circuit, and means to control the oscillations according to speech waves comprising a modulating arrangement connectedbetweenthe grids and the filaments formed of an inductance, a capacity in parallel with the inductance and a microphone inserted in the circuit formed by the said inductance and the said capacity.

6. A generator of continuous oscillations comprismg a plurality of thermionic tubes including filaments, grids and anodes, means for heating said filaments, a star-connected source of polyphase alternating current including an individual terminal for each phasewinding and a common point, means connecting each res ective terminal to the anode of one of sai tubes, means including i an inductance connecting the common point having their filament system and anodes connected in multiple which comprises introducing a separate phase of a polyphase alternating source in the anode-filament circuitof each of the thermionic tubes.

8. In a system of the class described, means for emitting electrons and a plurality of anodes operating in highly evacuated space, a polyphase source of. electromotive forces to provide one phase for each anode whereby a plurality of substantially pure electron currents are developed, and a. utilization circuit in which said electron currents are combined.

9. In a'system of the class described, means for emitting electrons, a lurality of anodes, a polyphase source of e ectromotive forces to provide one phase for each anode whereby v menace a plurality of space currents are developed, means for regeneratively controlling said space currents, and a utilization circuit in which said controlled space currents are combined.

10. The method of generating oscillations which consists in producing a plurality of substantially pure electron currents under the control of alternating polyphase voltages, electrostaticall controlling said space currents by energy erived from said space currents, and combining said controlled space currents.

11; The method of generating oscillations which consists in producing a plurality of oscillating electron currents substantially free from ionization effects under the control of alternating polyphase voltages by applying said alternating polyphase voltages so that said currents reach their maximum value and minimum value in succession.

12. The method of generating oscillations which consists in producing a plurality of space currents under the control of alternating polyphase voltages, controlling said space currents by energy derived regeneratively from said space currents, and combining said regeneratively controlled space currents.

13. The method of signalling Which consists in producing a plurality of oscillating electron currents under the control of alternating polyphase voltages, combining said oscillating electron currents and modulating said combined oscillating electron currents.

14. In a system for generating high frequency continuous oscillations, an alternating polyphase energy source, a plurality of thermionic tubes having their filaments and their grids connected respectively in multiple, an inductance through Which said groups of grids and filaments are connected, each of the anodes of said tubes being connected to a diiferent phase of said alternating polyphase energy source to cause space currents to flow between said filaments and anodes, and means for introducing energy derived ,fromsaid space currents in said inductance.

MARIUS LATOUR. 

